Javascript 'while' 循环加载单页应用程序不起作用

Question

I am trying to load a single page app until I have certain number of Items. My function passes the correct new scrollHeight but the code does not work. Here is my code, I start it by calling scrollInitiate() function. What am I missing?

function wait(ms){
    var start = new Date().getTime();
    var end = start;
    while(end < start + ms) {
      end = new Date().getTime();
   }
 }


function scrollInitiate() {
    while ($x('//*[@id="items"]/container').length < 200) {
        console.log("attempting");
        wait(5000);
        scrollIt(document.scrollingElement.scrollHeight);
    }
}

function scrollIt(height) {
    console.log("scrolling to: " + height);
    document.scrollingElement.scrollTo(0, height);
}

Answer 1

You can't use while to wait in javascript, due to javascript blocking nature. Instead use setTimeout :

function scrollInitiate() {
  if ($x('//*[@id="items"]/container').length < 200) {
    console.log("attempting");
    scrollIt(document.scrollingElement.scrollHeight);
    setTimeout(scrollInitiate, 5000);
  }
  console.log("success");
}